溶胶-凝胶和浸渍法制备的铜催化剂在仲丁醇脱氢反应中的研究

采用溶胶-凝胶和浸渍法制备Cu/SiO2催化剂, 研究了不同制备方法对催化剂表面Cu物种的存在状态和其催化性能的影响. 采用BET, XRD, EPR和TPR等手段对催化剂进行了表征, 结果表明, 溶胶-凝胶法可制备高分散铜催化剂, 该催化剂中存在孤立的不可还原的Cu2+和可还原的Cu2+簇两种物种. 浸渍法制备的催化剂中含有可还原的Cu2+簇物种. 反应活性测试结果表明, 不可还原的孤立Cu2+呈高分散状态, 但其对仲丁醇脱氢反应没有活性; 可还原的Cu2+在反应过程中被还原成Cu0, Cu0是反应稳定脱氢的活性中心.

Studies on Dehydrogenation of 2-Butanol over Supported Copper Catalysts Prepared by Sol-Gel and Impregnation Methods

The Cu/SiO2 catalysts were prepared by sol-gel and impregnation methods.The effect of the diffe-rent preparing methods and contents of copper on the structure and property of the catalysts was studied,and the activity of these catalysts on the dehydrogenation of 2-butanol and the selectivity for MEK were also investigated.These catalysts were characterized by means of BET,XRD,EPR and TPR.The results indicat that the high dispersing copper catalysts could be prepared by using sol-gel method.There were two kinds of copper species on the surface of catalysts,one was the unreduced isolated Cu2 ,the other was the copper oxide clusters.There was only the copper oxide clusters on the catalyst prepared by impregnation method.The results show that the isolated Cu2 was inactive for dehydrogenation of 2-butanol.The copper oxide clusters could be reduced to Cu0 during the reaction,Cu0 was the main stable active sites for this reaction.